Safety hook for patient lift

ABSTRACT

The invention relates to a safety hook for mounting on the extremity of a spreader bar ( 1 ) of a patient lift. The safety hook comprises a base member ( 5 ) that is connected to or integral with the spreader bar ( 1 ). A load-bearing hook member ( 2 ) is pivotally suspended from the base member ( 5 ) to allow the hook member ( 2 ) to move in the plane of the hook member ( 2 ) between an open position and a closed position in which the free end of the hook member ( 2 ) engages the base member ( 5 ) at an engagement point ( 15 ). The hook member ( 2 ) is shaped such that it is urged to the closed position when a downward load is applied to it, and that it is urged to the open position when an upward load is applied to it. Retaining means keep the hook member ( 2 ) in both the open position and in the closed position unless a substantial force is applied to the hook member.

The present invention relates to a safety hook for mounting on theextremity of a spreader bar of a patient lift of the type that comprisesa base member, a load-bearing hook member extending in a first plane andhaving a first end and a second free end.

BACKGROUND ART

The hooks on the extremities of the spreader bar of a patient lift usedfor attaching a sling, harness or lifting belt to the spreader bar of apatient lift are normally provided with measures to minimize the risk ofunintentional release of the attachment loops at the free ends of thesupport straps of the sling, harness or lifting belt. These measuresusually comprise double hooks creating a labyrinth, corkscrew hooks, orresilient clips (snap finger) or other resilient means that close theopening of a simple hook. All of these measures have in common that theoperation of attaching and detaching an attachment loop from the hook iscumbersome and the operator usually needs to use both hands.

DISCLOSURE OF THE INVENTION

Against this background, it is an object of the present invention toprovide a safety hook for a patient lift of the kind referred toinitially, that allows comfortable detachment and attachment ofattachment loops. This object is achieved in accordance with claim 1 byproviding a hook of said kind in which the first end is pivotallysuspended from the base member at a pivot axis to allow the hook memberto move in the plane of the hook member between an open position and aclosed position in which the free end of the hook member engages thebase member at an engagement point, and whereby the hook member extendsfrom the pivot axis to one side of a second plane which falls togetherwith the pivot axis and the engagement point, the hook member extendingfurther through the second plane to its free end.

Thus, the hook member is shaped such that it is urged to the closedposition when a downward load is applied to it, and urged to the openposition when an upward load is applied to it. Under normalcircumstances the safety hook closes automatically under the weight ofthe load. Unintentional opening of the safety hook is excluded as therecan there cannot be an upward load under normal circumstances. Releasinga sling or lifting belt from the safety hook is very simple, theoperator merely needs to pull the attachment loop of the sling orlifting belt upwards to open the safety hook and the attachment loop canbe released.

The safety hook may comprise means for retaining the hook member in theclosed position, these means preferably comprising a resiliently biasedlocking member in the base member for engaging a first recess in thehook member.

Thus, the chance that the hook member moves out of the closed positiondue to e.g. violent movements of the spreader bar is minimized.

The safety hook may comprise means for retaining the hook member in theopen position, these means preferably comprising the resiliently biasedlocking member in the base member for engaging a second recess in thehook member.

Thus, the hook member can remain in the open position for attaching ordetaching a load such as the attachment loop of a sling.

The safety hook may be constructed such that the free end of the hookmember positively engages the base member at the engagement point,preferably by complementary shapes provided on the free en of the hookmember and on the base member at the engagement point.

Thus, the chance that the hook member deforms under an extreme load isreduced.

The base member can an integral part of the spreader bar or can beattached to the spreader bar.

The second plane is preferably substantially parallel with the spreaderbar, with the hook member extending downwards from the pivot axis sothat a downward load applied on the hook member urges it to the closedposition.

The hook member preferably comprises a part proximate to the free endthat extends substantially parallel with the spreader bar so that anupward load applied on the hook member urges it to the open position.

Further objects, features, advantages and properties of the safety hookaccording to the invention will become apparent from the detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present description, theinvention will be explained in more detail with reference to theexemplary embodiments shown in the drawings, in which:

FIG. 1 is a view of a part of a patient lifting system,

FIG. 2 is a side view of a spreader bar provided with safety hooksaccording to the present invention,

FIG. 3 is a perspective view of a safety hook according to the presentinvention,

FIG. 4 is a cross-sectional view of the safety hook according to thepresent invention in an open position, and

FIG. 5 is a cross-sectional view of the safety hook according to thepresent invention in a closed position.

DETAILED DESCRIPTION

A part of a patient lift system is illustrated in FIG. 1, comprising aspreader bar 1 suspended from a connection point 4 in the middle on topby a strap or wire from a not shown lifting device. Suitable liftingdevices are e.g.

ceiling lifts operating with an overhead rail from which the spreaderbar is suspended by a strap, or cable, usually via a winch, or

floor lifts operating with a wheeled frame provided with a mast and alifting arm to which the wire or strap is connected, all well known inthe art.

Hook members 2 extend from both horizontal extremities of the spreaderbar 1. The patient to be lifted is carried by a sling 3. The sling 3 isprovided with a plurality of support straps provided with attachmentloops at their free ends. The attachment loops are securely hung overthe safety hooks 2. Other types of slings such as walking slings,stretcher slings, lifting belts, patient harness or other devices usedfor supporting a patient to be lifted can be used instead of the slingshown in FIG. 1.

FIG. 2 shows a side view of the spreader bar 1 in greater detail. Thespreader bar 1 is shaped as a curved bar (straight bars, or bars formedby two straight parts at an angle (cf. FIG. 1) are equally suitable). Abase member 5 of the safety hook according to the invention is mountedat each horizontal extremity of the spreader bar 1. A hook member 2 issuspended from each of the base members 5.

FIG. 3 shows a perspective view of a safety hook according to theinvention in even greater detail. The main body of the base member 5 isformed by a substantially cylindrical body, but any other shape could beused instead. The hook member 2 is at a first end suspended from thebase member 2 by a pivot shaft 8. The second free end of the hook member2 is provided with a substantially ball shaped projection 6. The basemember is provided with a complementary spherical recess 7 for receivingthe ball shaped projection 6.

FIGS. 4 and 5 show a safety hook according to the invention incross-sectional views in the open and the closed position respectively.The base member 2 is provided with a slot 14 for receiving a part of thehook member 2. The pivot shaft 8 extends through the slot 14 and throughthe first end of the hook member 2, allowing the latter to be suspendedfrom the base member so that it can rotate in the plane of the hookmember 2 between an open position (cf. FIG. 4) and a closed position(cf. FIG. 5).

The base member is provided with a channel 9 that opens into the slot 14so that it faces the first end of the hook member 2. A spring 11arranged in the channel 9 urges a ball 10 towards the first end of thehook member 2. The first end of the hook member 2 is provided with arecess 12 for engaging the spring loaded ball 10 in the closed position,and with a with a recesses 13 for engaging the spring loaded ball 10 inthe open position.

When the hook member is moved to the open position or to the closedposition the spring loaded ball 10 snaps into the respective recess12,13 and thus the hook member is retained either the open position orin the closed position unless a substantial force is applied to move thehook member to the other position.

In the open position an attachment loop of e.g. a sling 3 can easily behung over the hook member 2. This operation can, if necessary, becarried using only one hand, since the hook member 2 stays in the openposition because the gravity force caused by the weight of the hookmember 2 alone is not sufficient to overcome the resistance of thespring loaded ball 10.

When a load is applied, e.g. when a patient takes place in the sling 3,the downward force applied to the hook member is big enough to overcomethe retaining force created by the spring loaded ball 10 and the hookmember moves to the closed position in which the ball shaped protrusion6 at free end of the hook member 2 positively engages the sphericalrecess 7 at a contact point 15. The positive engagement increases theoverall stability of the safety hook, and minimizes the risk ofdeformation of the hook member 2 under excessive load.

The hook member 2 and the base member 5 form a closed loop and as longas the hook member 2 stays in the closed position any attachment loopshung over the hook member 2 cannot be unintentionally be disengaged fromthe safety hook. Under normal circumstance the load itself prevents thehook member 2 to move unintentionally to the open position. The springloaded ball 10 ensures that the hook member 2 also remains in the closedposition even if the load does not apply a downward force, e.g. forshort periods of time caused by violent movements of the spreader bar 1.The risk of an attachment loop of a sling 3 to disengage unintentionallyis therefore minimized.

The attachment loop can be disengaged from the safety hook by a usersimply pulling the attachment loop upwards with a force sufficient toovercome the retaining force of the spring loaded ball 10, and thus movethe hook member 2 to the open position where it is retained again by thespring loaded ball 10. When the safety hook is open the attachment loopor loops can be removed from the hook member 2 to disengage the sling 3

Line 16 represents an imaginary plane that falls together with the pivotaxis of shaft 8 and the contact point 15 where the free end 6 of thehook member 2 engages the base member 5. The hook member 2 extends fromits first end to the lower side of the imaginary plane and turns upwardsthough the imaginary plans until its free end that is on the upper sideof the imaginary plane. Any such shaped hook member is suitable for usewith the present invention, since it will automatically lock under load.

The use of the safety hook as described with reference to the preferredembodiments is not limited to mounting on spreader bars of ceilinglifts. The lifts could be floor lifts, and the hook may e.g. also bemounted on the end of the lifting arm of a floor lift.

Although the present invention has been described in detail for purposeof illustration, it is understood that such detail is solely for thatpurpose, and variations can be made therein by those skilled in the artwithout departing from the scope of the invention.

Thus, while the preferred embodiments of the devices and methods havebeen described in reference to the environment in which they weredeveloped, they are merely illustrative of the principles of theinventions. Other embodiments and configurations may be devised withoutdeparting from the scope of the appended claims.

1. A safety hook for mounting on the extremity of a spreader bar (1) ofa patient lift comprising: a base member (5), a load-bearing hook member(2) extending in a first plane and having a first end and a second freeend, characterized by the first end being pivotally suspended from thebase member (5) at a pivot axis to allow the hook member (2) to move inthe first plane between an open position and a closed position in whichthe free end of the hook member engages the base member at an engagementpoint (15), and whereby the hook member (2) extends from the pivot axisto one side of a second plane which falls together with the pivot axisand the engagement point (15), the hook member (2) extending furtherthrough the second plane to its free end.
 2. A safety hook according toclaim 1, further comprising means for retaining the hook member (2) inthe closed position, these means comprising a resiliently biased lockingmember (10) in the base member (5) for engaging a first recess (12) inthe hook member (2).
 3. A safety hook according to claim 2, furthercomprising means for retaining the hook member (2) in the open position,these means comprising the resiliently biased locking member (10) in thebase member (5) for engaging a second recess (13) in the hook member(2).
 4. A safety hook according to claim 3, wherein the free end of thehook member (2) positively engages the base member (5) at the engagementpoint (15), by complementary shapes (6,7) provided on the free end ofthe hook member (2) and on the base member (5) at the engagement point(15).
 5. A safety hook according to claim 1, wherein the base member (5)is an integral part of the spreader bar (1).
 6. A safety hook accordingto claim 1, wherein the second plane is substantially parallel with thespreader bar (1), with the hook member (2) extending downwards from thepivot axis so that a downward load applied on the hook member (2) urgesit to the closed position.
 7. A safety hook according to claim 6,wherein the hook member (2) comprises a part proximate to the free-endthat extends substantially parallel with the spreader bar (1) so that anupward load applied on the hook member (2) urges it to the openposition.